The Cro-Magnons were the creators of the cave paintings at Lascaux and Altamira – the ice age hunter gatherers whose art astounds us (“We have learned nothing,” said Picasso, after seeing Lascaux). They were modern humans who entered Europe only about 40,000 years ago, and there, despite the hostile ice age environment, created the first artistically sophisticated culture. But that wasn’t the end of human evolution. Modern genomics has now shown us that biological evolution actually accelerated from this point on, especially since the beginning of farming 10,000 years ago.

Stringer is most concerned with the period from the emergence of Homo sapiens in Africa, around 195,000 years ago, to their arrival in Europe and the subsequent demise of the Neanderthals (who had left Africa hundreds of thousands of years before). The archaeological record shows Homo sapiens in Africa several times on the verge of a cultural breakthrough, but this is not consolidated until their arrival in Europe. Stringer writes: “It is as though the candle glow of modernity was intermittent, repeatedly flickering on and off again.”

Last year, the Neanderthal Genome Project, led by the Swedish biologist Svante Pääbo, finally established that modern humans in Europe and Asia (but not Africa) have some admixture of Neanderthal genes, thus ending decades of speculation. And in December last year the same team produced a total surprise: a genomic analysis of human remains from a cave in Denisova, southern Siberia, which proved to be genetically distinct from all known human types. The team declined at this stage to give the find a Linnean species name, but, by analogy with the Neanderthals, named it Denisovan after the location. The actual Denisovan specimens in Siberia were 30-50,000 years old, and the type predated both modern humans and Neanderthals.

Apart from having what is probably a new species to fit into the pattern of human evolution, the big shock of the Denisovans is that they also have contributed something to the modern human stock in Melanesia (the islands north of Australia that include Papua New Guinea). We now see a pattern emerging of interbreeding between modern humans and earlier types: Neanderthals in Europe and Asia and Denisovans in Melanesia. There will surely be further finds. Especially interesting is East Asia, first peopled by Homo erectus as long as 1.7m years ago.